Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 24
Filter
1.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-336041

ABSTRACT

Background Understanding immunological responses to SARS-CoV-2 vaccinations is integral to the management of SARS-CoV-2. We aimed to investigate determinants of antibody response to the BNT162b2 vaccine. Methods A cross-sectional analysis of anti-spike binding antibodies in serum samples from healthcare workers after one or two doses. Post-vaccination interval was restricted to ≥21 days after dose 1, ≥14 days after dose 2. The primary outcome was anti-S titres with explanatory variables dose, previous infection, dosing interval, age, ethnicity, and comorbidities. Multivariable linear regression was also conducted. Results Participants (n=5,871) included 3,989 post-dose 1, 1,882 post-dose 2. In SARS-CoV-2 infection naïve, 99.65% seroconverted after dose 1 and >99.9% seroconverted after dose 2. Geometric mean anti-S titre in the naïve cohort was 75.48 Binding Antibody Units/ml after dose 1, 7,049 BAU/ml after dose 2. Anti-S titres were higher in those with previous infection (2,111 BAU/ml post-dose 1, 16,052 BAU/ml post-dose 2), and increased with time between infection and vaccination: 3 months 1,970 (1,506-2,579) vs 9 months;13,759 (8,097-23,379). Longer dosing intervals increased antibody response post-dose 2: 11-fold higher with a longer interval (>10 weeks) than those with shorter intervals, across all age-groups. Younger participants had higher mean titres (>2.2-fold higher). Multivariable regression modelling corroborated the above associations, and also found higher titres associated with being female or from an ethnic minority but lower titres among immunocompromised participants. Conclusion The number of antigen exposures and timing between vaccinations plays a significant role in the magnitude of the post-vaccination antibody response, with implications for long-term protection and post-booster antibody responses.

2.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-329110

ABSTRACT

Background: SARS-CoV-2 is known to transmit in hospital settings, but the contribution of infections acquired in hospitals to the epidemic at a national scale is unknown. Methods: We used comprehensive national English datasets to determine the number of COVID-19 patients with identified hospital-acquired infections (with symptom onset >7 days after admission and before discharge) in acute English hospitals up to August 2020. As patients may leave the hospital prior to detection of infection or have rapid symptom onset, we combined measures of the length of stay and the incubation period distribution to estimate how many hospital-acquired infections may have been missed. We used simulations to estimate the total number (identified and unidentified) of symptomatic hospital-acquired infections, as well as infections due to onward community transmission from missed hospital-acquired infections, to 31 st July 2020. Results: In our dataset of hospitalised COVID-19 patients in acute English hospitals with a recorded symptom onset date (n = 65,028), 7% were classified as hospital-acquired. We estimated that only 30% (range across weeks and 200 simulations: 20-41%) of symptomatic hospital-acquired infections would be identified, with up to 15% (mean, 95% range over 200 simulations: 14.1%-15.8%) of cases currently classified as community-acquired COVID-19 potentially linked to hospital transmission. We estimated that 26,600 (25,900 to 27,700) individuals acquired a symptomatic SARS-CoV-2 infection in an acute Trust in England before 31st July 2020, resulting in 15,900 (15,200-16,400) or 20.1% (19.2%-20.7%) of all identified hospitalised COVID-19 cases. Conclusions: Transmission of SARS-CoV-2 to hospitalised patients likely caused approximately a fifth of identified cases of hospitalised COVID-19 in the “first wave” in England, but less than 1% of all infections in England. Using time to symptom onset from admission for inpatients as a detection method likely misses a substantial proportion (>60%) of hospital-acquired infections.

3.
N Engl J Med ; 386(13): 1207-1220, 2022 03 31.
Article in English | MEDLINE | ID: covidwho-1692473

ABSTRACT

BACKGROUND: The duration and effectiveness of immunity from infection with and vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are relevant to pandemic policy interventions, including the timing of vaccine boosters. METHODS: We investigated the duration and effectiveness of immunity in a prospective cohort of asymptomatic health care workers in the United Kingdom who underwent routine polymerase-chain-reaction (PCR) testing. Vaccine effectiveness (≤10 months after the first dose of vaccine) and infection-acquired immunity were assessed by comparing the time to PCR-confirmed infection in vaccinated persons with that in unvaccinated persons, stratified according to previous infection status. We used a Cox regression model with adjustment for previous SARS-CoV-2 infection status, vaccine type and dosing interval, demographic characteristics, and workplace exposure to SARS-CoV-2. RESULTS: Of 35,768 participants, 27% (9488) had a previous SARS-CoV-2 infection. Vaccine coverage was high: 95% of the participants had received two doses (78% had received BNT162b2 vaccine [Pfizer-BioNTech] with a long interval between doses, 9% BNT162b2 vaccine with a short interval between doses, and 8% ChAdOx1 nCoV-19 vaccine [AstraZeneca]). Between December 7, 2020, and September 21, 2021, a total of 2747 primary infections and 210 reinfections were observed. Among previously uninfected participants who received long-interval BNT162b2 vaccine, adjusted vaccine effectiveness decreased from 85% (95% confidence interval [CI], 72 to 92) 14 to 73 days after the second dose to 51% (95% CI, 22 to 69) at a median of 201 days (interquartile range, 197 to 205) after the second dose; this effectiveness did not differ significantly between the long-interval and short-interval BNT162b2 vaccine recipients. At 14 to 73 days after the second dose, adjusted vaccine effectiveness among ChAdOx1 nCoV-19 vaccine recipients was 58% (95% CI, 23 to 77) - considerably lower than that among BNT162b2 vaccine recipients. Infection-acquired immunity waned after 1 year in unvaccinated participants but remained consistently higher than 90% in those who were subsequently vaccinated, even in persons infected more than 18 months previously. CONCLUSIONS: Two doses of BNT162b2 vaccine were associated with high short-term protection against SARS-CoV-2 infection; this protection waned considerably after 6 months. Infection-acquired immunity boosted with vaccination remained high more than 1 year after infection. (Funded by the U.K. Health Security Agency and others; ISRCTN Registry number, ISRCTN11041050.).


Subject(s)
Adaptive Immunity , COVID-19 Vaccines , COVID-19 , SARS-CoV-2 , Adaptive Immunity/immunology , Asymptomatic Diseases , 59828/therapeutic use , COVID-19/diagnosis , COVID-19/immunology , COVID-19/prevention & control , COVID-19 Nucleic Acid Testing , COVID-19 Vaccines/immunology , COVID-19 Vaccines/therapeutic use , 59831/therapeutic use , Health Personnel , Humans , Prospective Studies , United Kingdom , Vaccination/methods , 59641
4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-311891

ABSTRACT

Background: BNT162b2 mRNA and ChAdOx1 nCOV-19 adenoviral vector vaccines have been rapidly rolled out in the UK. We determined the factors associated with vaccine coverage for both vaccines and documented the vaccine effectiveness of the BNT162b2 mRNA vaccine in our healthcare worker (HCW) cohort study of staff undergoing regular asymptomatic testing.Methods: The SIREN study is a prospective cohort study among staff working in publicly funded hospitals. Baseline risk factors, vaccination status (from 8/12/2020-5/2/2021), and symptoms are recorded at 2 weekly intervals and all SARS-CoV-2 polymerase chain reaction (PCR) and antibody test results documented. A mixed effect proportional hazards frailty model using a Poisson distribution was used to calculate hazard ratios to compare time to infection in unvaccinated and vaccinated participants to estimate the impact of the BNT162b2 vaccine on all (asymptomatic and symptomatic) infection.Findings: Vaccine coverage was 89% on 5/2/2021. Significantly lower coverage was associated with prior infection (aOR 0.59 95% confidence interval [CI] 0.54-0.64), female (aOR 0.72, 95% CI 0.63-0.82), aged under 35 years, being from minority ethnic groups (especially Black, aOR 0.26, 95% CI 0.21-0.32), porters/security guards (aOR 0.61, 95% CI 0.42-0.90),or midwife (aOR 0.74, 95% CI 0.57-0.97), and living in more deprived neighbourhoods (IMD 1 (most) vs. 5 (least) (aOR 0.75, 95% CI 0.65-0.87). A single dose of BNT162b2 vaccine demonstrated vaccine effectiveness of 72% (95% CI 58-86) 21 days after first dose and 86% (95% CI 76-97) seven days after two doses in the antibody negative cohort.Conclusion: Our study demonstrates that the BNT162b2 vaccine effectively prevents both symptomatic and asymptomatic infection in working age adults;this cohort was vaccinated when the dominant variant in circulation was B1.1.7 and demonstrates effectiveness against this variant.Trial Registration: IRAS ID 284460, REC reference 20/SC/0230 Berkshire Research Ethics Committee, Health Research Authority and Health and Care Research Wales approval granted 22 May 2020. Trial registered with ISRCTN, Trial ID: ISRCTN11041050. https://www.isrctn.com/ISRCTN11041050Funding: The study is funded by the United Kingdom’s Department of Health and Social Care and Public Health England, with contributions from the Scottish, Welsh and Northern Irish governments. Funding is also provided by the National Institute for Health Research (NIHR) as an Urgent Public Health Priority Study (UPHP). SH, VH are supported by the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Healthcare Associated Infections and Antimicrobial Resistance at the University of Oxford in partnership with Public Health England (PHE) (NIHR200915). AC is supported by NIHR HealthProtection Research Unit in Behavioural Science and Evaluation at University of Bristol in partnership with Public Health England. MR, NA, AC are supported by NIHR HealthProtection Research Unit in Immunisation at the London School of Hygiene and Tropical Medicine in partnership with Public Health England.Conflict of Interest: The Immunisation and Countermeasures Division has provided vaccine manufacturers(including Pfizer) with post-marketing surveillance reports on pneumococcal andmeningococcal infection which the companies are required to submit to the UK Licensing authority in compliance with their Risk Management Strategy. A cost recovery charge is made for these reports.Ethical Approval: The study was approved by the Berkshire Research Ethics Committee, Health Research Authority (IRAS ID 284460, REC reference 20/SC/0230) on 22 May 2020;the vaccine amendment was approved on 12/1/2021.

5.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327437

ABSTRACT

Objectives To explore attitudes and intentions towards COVID-19 vaccination, and influences and sources of information about COVID-19 across diverse ethnic groups (EGs) in the UK. Design Remote qualitative interviews and focus groups (FGs) conducted June-October 2020 before UK COVID-19 vaccine approval. Data were transcribed and analysed through inductive thematic analysis. Setting General public in the community across England and Wales. Participants 100 participants from 19 self-identified EGs with spoken English or Punjabi. Results Mistrust and doubt were common themes across all EGs including white British and minority EGs, but more pronounced amongst Bangladeshi, Pakistani, Black ethnicities and Travellers. Many participants shared concerns about perceived lack of information about COVID-19 vaccine safety, efficacy and potential unknown adverse effects. Across EGs participants stated occupations with public contact, older adults and vulnerable groups should be prioritised for vaccination. Perceived risk, social influences, occupation, age, co-morbidities and engagement with healthcare influenced participants’ intentions to accept vaccination once available;all Jewish FG participants intended to accept, while all Traveller FG participants indicated they probably would not. Facilitators to COVID-19 vaccine uptake across all EGs included: desire to return to normality and protect health and wellbeing;perceived higher risk of infection;evidence of vaccine safety and efficacy;vaccine availability and accessibility. COVID-19 information sources were influenced by social factors, culture and religion and included: friends, family;media and news outlets;and research literature. Participants across most different EGs were concerned about misinformation or had negative attitudes towards the media. Conclusions During vaccination programme roll-out, including boosters, commissioners and vaccine providers should provide accurate information, authentic community outreach, and use appropriate channels to disseminate information and counter misinformation. Adopting a context-specific approach to vaccine resources, interventions and policies and empowering communities has potential to increase trust in the programme. Article summary: strengths and limitations This is amongst the largest qualitative studies on attitudes to the COVID-19 pandemic in the UK general public across ethnic groups (EGs), ages and religions, adding insights from a broader range of participants. Qualitative methodology enabled discussion of participants’ responses around COVID-19 vaccination, probing to collect rich data to inform recommendations across EGs. Most data collection was undertaken in English, possibly excluding sectors of the population who may access COVID-19 information through different sources due to language. Data collection was June-October 2020 before COVID-19 vaccines were licensed. Attitudes are highly responsive to current information around a COVID-19 vaccine, as well as the state of the pandemic and perceived risk. Data were collected prior to much of the intervention work, putting the attitudes and intentions expressed in this study in a context of minimal community engagement and support. This provides a baseline snapshot of attitudes, providing the option to explore and assess the impact of such interventions. Socioeconomic data and index of multiple deprivation were not collected, limiting the ability to determine a possible accumulative effect of factors such as socioeconomic status, ethnicity and age.

6.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327367

ABSTRACT

Objectives: To explore public reactions to the COVID-19 pandemic across diverse ethnic groups. Design Remote qualitative interviews and focus groups in English or Punjabi. Data were transcribed and analysed through inductive thematic analysis. Setting England and Wales June-October 2020. Participants 100 participants from 19 diverse self-identified ethnic groups. Results Dismay, frustration and altruism were reported across all ethnic groups during the first six to nine months of the COVID-19 pandemic. Dismay was caused by participants reported individual, family and community risks, and loss of support networks. Frustration was caused by reported lack of recognition of the efforts of minority ethnic groups (MEGs), inaction by government to address COVID-19 and inequalities, rule breaking by government advisors, changing government rules around: border controls, personal protective equipment, social distancing, eating out, and perceived poor communication around COVID-19 and the Public Health England (PHE) COVID-19 disparities report (leading to reported increased racism and social isolation). Altruism was felt by all, in the resilience of NHS staff and their communities and families pulling together. Data, participants suggested actions, and the Behaviour Change Wheel informed suggested interventions and policies to help control COVID-19. Conclusion To maintain public trust, it is imperative that governmental bodies consider vulnerable groups, producing clear COVID-19 control guidance with contingency, fiscal, service provision and communication policies for the next rise in COVID-19 cases. This needs to be combined with public interventions including information, education, modelling and enablement of infection prevention through local community involvement and persuasion techniques or incentivisation. Government policy needs to review and include town and social planning leading to environmental restructuring that facilitates infection prevention control. This includes easy access to hand-washing facilities in homes, work, all food providers and shopping centres;toilet facilities as our Travellers mentioned, and adequate living accommodation and work environment facilitating IPC for all.

7.
BMJ ; 376: o35, 2022 01 17.
Article in English | MEDLINE | ID: covidwho-1627545
9.
J Antimicrob Chemother ; 77(3): 799-802, 2022 02 23.
Article in English | MEDLINE | ID: covidwho-1569708

ABSTRACT

BACKGROUND: Antibacterial prescribing for respiratory tract infections (RTIs) accounts for almost half of all prescribing in primary care. Nearly a quarter of antibacterial prescribing in primary care is estimated to be inappropriate, the greatest being for RTIs. The COVID-19 pandemic has changed the provision of healthcare services and impacted the levels of antibacterials prescribed. OBJECTIVES: To describe the changes in community antibacterial prescribing for RTIs in winter 2020-21 in England. METHODS: RTI antibacterial prescribing was measured in prescription items/1000 population for primary care from January 2014 and in DDDs/1000 population/day for the totality of RTI prescribing [combined with Accident & Emergency (A&E) in secondary care], from January 2016 to February 2021. Trends were assessed using negative binomial regression and seasonally adjusted interrupted time-series analysis. RESULTS: Antibacterials prescribed for RTIs reduced by a further 12.4% per season compared with pre-COVID (P < 0.001). In winter 2020-21, RTI prescriptions almost halved compared with the previous winter in 2019-20 (P < 0.001). The trend observed for total RTI prescribing (primary care with A&E) was similar to that observed in the community alone. CONCLUSIONS: During COVID-19, RTI prescribing reduced in the community and the expected rise in winter was not seen in 2020-21. We found no evidence that RTI prescribing shifted from primary care to A&E in secondary care. The most likely explanation is a decrease in RTIs and presentations to primary care associated with national prevention measures for COVID-19.


Subject(s)
COVID-19 , Respiratory Tract Infections , Anti-Bacterial Agents/therapeutic use , England/epidemiology , Humans , Inappropriate Prescribing/prevention & control , Pandemics , Practice Patterns, Physicians' , Primary Health Care , Respiratory Tract Infections/drug therapy , Respiratory Tract Infections/epidemiology , SARS-CoV-2 , Seasons
11.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-293307

ABSTRACT

Background: Understanding the duration and effectiveness of infection and vaccine-acquired SARS-CoV-2 immunity is essential to inform pandemic policy interventions, including the timing of vaccine-boosters. We investigated this in our large prospective cohort of UK healthcare workers undergoing routine asymptomatic PCR testing. Methods We assessed vaccine effectiveness (VE) (up to 10-months after first dose) and infection-acquired immunity by comparing time to PCR-confirmed infection in vaccinated and unvaccinated individuals using a Cox regression-model, adjusted by prior SARS-CoV-2 infection status, vaccine-manufacturer/dosing-interval, demographics and workplace exposures. Results Of 35,768 participants, 27% (n=9,488) had a prior SARS-CoV-2 infection. Vaccine coverage was high: 97% had two-doses (79% BNT162b2 long-interval, 8% BNT162b2 short-interval, 8% ChAdOx1). There were 2,747 primary infections and 210 reinfections between 07/12/2020 and 21/09/2021. Adjusted VE (aVE) decreased from 81% (95% CI 68%-89%) 14-73 days after dose-2 to 46% (95% CI 22%-63%) >6-months;with no significant difference for short-interval BNT162b2 but significantly lower aVE (50% (95% CI 18%-70%) 14-73 days after dose-2 from ChAdOx1. Protection from infection-acquired immunity showed evidence of waning in unvaccinated follow-up but remained consistently over 90% in those who received two doses of vaccine, even in those infected over 15-months ago. Conclusion Two doses of BNT162b2 vaccination induce high short-term protection to SARS-CoV-2 infection, which wanes significantly after six months. Infection-acquired immunity boosted with vaccination remains high over a year after infection. Boosters will be essential to maintain protection in vaccinees who have not had primary infection to reduce infection and transmission in this population. Trial registration number ISRCTN11041050

12.
Int J STD AIDS ; 33(2): 209-211, 2022 02.
Article in English | MEDLINE | ID: covidwho-1542033

ABSTRACT

We describe the case of a 30-year-old care home employee diagnosed with COVID-19 and acute untreated HIV-1. He was unable to return to work for 119 days due to concerns over transmission risk as his SARS-CoV-2 PCR remained detectable. This highlights the uncertainty in interpreting SARS-CoV-2 PCR results post-infection in acute untreated HIV.


Subject(s)
COVID-19 , HIV Infections , HIV-1 , Adult , HIV Infections/complications , HIV Infections/drug therapy , Humans , Male , Return to Work , SARS-CoV-2
13.
Lancet Microbe ; 3(2): e151-e158, 2022 02.
Article in English | MEDLINE | ID: covidwho-1440435

ABSTRACT

We reviewed all genomic epidemiology studies on COVID-19 in long-term care facilities (LTCFs) that had been published to date. We found that staff and residents were usually infected with identical, or near identical, SARS-CoV-2 genomes. Outbreaks usually involved one predominant cluster, and the same lineages persisted in LTCFs despite infection control measures. Outbreaks were most commonly due to single or few introductions followed by a spread rather than a series of seeding events from the community into LTCFs. The sequencing of samples taken consecutively from the same individuals at the same facilities showed the persistence of the same genome sequence, indicating that the sequencing technique was robust over time. When combined with local epidemiology, genomics allowed probable transmission sources to be better characterised. The transmission between LTCFs was detected in multiple studies. The mortality rate among residents was high in all facilities, regardless of the lineage. Bioinformatics methods were inadequate in a third of the studies reviewed, and reproducing the analyses was difficult because sequencing data were not available in many facilities.


Subject(s)
COVID-19 , COVID-19/epidemiology , Disease Outbreaks , Genomics , Humans , Long-Term Care , SARS-CoV-2/genetics
14.
Clin Microbiol Infect ; 27(11): 1658-1665, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1392218

ABSTRACT

OBJECTIVES: The impact of bacterial/fungal infections on the morbidity and mortality of persons with coronavirus disease 2019 (COVID-19) remains unclear. We have investigated the incidence and impact of key bacterial/fungal infections in persons with COVID-19 in England. METHODS: We extracted laboratory-confirmed cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (1st January 2020 to 2nd June 2020) and blood and lower-respiratory specimens positive for 24 genera/species of clinical relevance (1st January 2020 to 30th June 2020) from Public Health England's national laboratory surveillance system. We defined coinfection and secondary infection as a culture-positive key organism isolated within 1 day or 2-27 days, respectively, of the SARS-CoV-2-positive date. We described the incidence and timing of bacterial/fungal infections and compared characteristics of COVID-19 patients with and without bacterial/fungal infection. RESULTS: 1% of persons with COVID-19 (2279/223413) in England had coinfection/secondary infection, of which >65% were bloodstream infections. The most common causative organisms were Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. Cases with coinfection/secondary infections were older than those without (median 70 years (IQR 58-81) versus 55 years (IQR 38-77)), and a higher percentage of cases with secondary infection were of Black or Asian ethnicity than cases without (6.7% versus 4.1%, and 9.9% versus 8.2%, respectively, p < 0.001). Age-sex-adjusted case fatality rates were higher in COVID-19 cases with a coinfection (23.0% (95%CI 18.8-27.6%)) or secondary infection (26.5% (95%CI 14.5-39.4%)) than in those without (7.6% (95%CI 7.5-7.7%)) (p < 0.005). CONCLUSIONS: Coinfection/secondary bacterial/fungal infections were rare in non-hospitalized and hospitalized persons with COVID-19, varied by ethnicity and age, and were associated with higher mortality. However, the inclusion of non-hospitalized persons with asymptomatic/mild COVID-19 likely underestimated the rate of secondary bacterial/fungal infections. This should inform diagnostic testing and antibiotic prescribing strategy.


Subject(s)
Bacterial Infections , COVID-19 , Coinfection , Mycoses , Adult , Aged , Bacterial Infections/epidemiology , COVID-19/epidemiology , Coinfection/epidemiology , England/epidemiology , Humans , Middle Aged , Mycoses/epidemiology
16.
Microb Genom ; 7(6)2021 06.
Article in English | MEDLINE | ID: covidwho-1349846

ABSTRACT

The COVID-19 pandemic has spread rapidly throughout the world. In the UK, the initial peak was in April 2020; in the county of Norfolk (UK) and surrounding areas, which has a stable, low-density population, over 3200 cases were reported between March and August 2020. As part of the activities of the national COVID-19 Genomics Consortium (COG-UK) we undertook whole genome sequencing of the SARS-CoV-2 genomes present in positive clinical samples from the Norfolk region. These samples were collected by four major hospitals, multiple minor hospitals, care facilities and community organizations within Norfolk and surrounding areas. We combined clinical metadata with the sequencing data from regional SARS-CoV-2 genomes to understand the origins, genetic variation, transmission and expansion (spread) of the virus within the region and provide context nationally. Data were fed back into the national effort for pandemic management, whilst simultaneously being used to assist local outbreak analyses. Overall, 1565 positive samples (172 per 100 000 population) from 1376 cases were evaluated; for 140 cases between two and six samples were available providing longitudinal data. This represented 42.6 % of all positive samples identified by hospital testing in the region and encompassed those with clinical need, and health and care workers and their families. In total, 1035 cases had genome sequences of sufficient quality to provide phylogenetic lineages. These genomes belonged to 26 distinct global lineages, indicating that there were multiple separate introductions into the region. Furthermore, 100 genetically distinct UK lineages were detected demonstrating local evolution, at a rate of ~2 SNPs per month, and multiple co-occurring lineages as the pandemic progressed. Our analysis: identified a discrete sublineage associated with six care facilities; found no evidence of reinfection in longitudinal samples; ruled out a nosocomial outbreak; identified 16 lineages in key workers which were not in patients, indicating infection control measures were effective; and found the D614G spike protein mutation which is linked to increased transmissibility dominates the samples and rapidly confirmed relatedness of cases in an outbreak at a food processing facility. The large-scale genome sequencing of SARS-CoV-2-positive samples has provided valuable additional data for public health epidemiology in the Norfolk region, and will continue to help identify and untangle hidden transmission chains as the pandemic evolves.


Subject(s)
COVID-19/pathology , Genome, Viral , SARS-CoV-2/genetics , COVID-19/epidemiology , COVID-19/virology , Cluster Analysis , Disease Outbreaks , Genetic Linkage , Humans , Longitudinal Studies , Pandemics , Phylogeny , Polymorphism, Single Nucleotide , SARS-CoV-2/classification , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/genetics , United Kingdom/epidemiology , Whole Genome Sequencing
17.
Emerg Infect Dis ; 27(7): 1795-1801, 2021 07.
Article in English | MEDLINE | ID: covidwho-1278355

ABSTRACT

We describe results of testing blood donors in London, UK, for severe acute respiratory disease coronavirus 2 (SARS-CoV-2) IgG before and after lockdown measures. Anonymized samples from donors 17-69 years of age were tested using 3 assays: Euroimmun IgG, Abbott IgG, and an immunoglobulin receptor-binding domain assay developed by Public Health England. Seroprevalence increased from 3.0% prelockdown (week 13, beginning March 23, 2020) to 10.4% during lockdown (weeks 15-16) and 12.3% postlockdown (week 18) by the Abbott assay. Estimates were 2.9% prelockdown, 9.9% during lockdown, and 13.0% postlockdown by the Euroimmun assay and 3.5% prelockdown, 11.8% during lockdown, and 14.1% postlockdown by the receptor-binding domain assay. By early May 2020, nearly 1 in 7 donors had evidence of past SARS-CoV-2 infection. Combining results from the Abbott and Euroimmun assays increased seroprevalence by 1.6%, 2.3%, and 0.6% at the 3 timepoints compared with Euroimmun alone, demonstrating the value of using multiple assays.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Blood Donors , Communicable Disease Control , England , Humans , Immunoglobulin G , London/epidemiology , Public Health , Sensitivity and Specificity , Seroepidemiologic Studies , United Kingdom
18.
Lancet ; 397(10286): 1725-1735, 2021 05 08.
Article in English | MEDLINE | ID: covidwho-1201329

ABSTRACT

BACKGROUND: BNT162b2 mRNA and ChAdOx1 nCOV-19 adenoviral vector vaccines have been rapidly rolled out in the UK from December, 2020. We aimed to determine the factors associated with vaccine coverage for both vaccines and documented the vaccine effectiveness of the BNT162b2 mRNA vaccine in a cohort of health-care workers undergoing regular asymptomatic testing. METHODS: The SIREN study is a prospective cohort study among staff (aged ≥18 years) working in publicly-funded hospitals in the UK. Participants were assigned into either the positive cohort (antibody positive or history of infection [indicated by previous positivity of antibody or PCR tests]) or the negative cohort (antibody negative with no previous positive test) at the beginning of the follow-up period. Baseline risk factors were collected at enrolment, symptom status was collected every 2 weeks, and vaccination status was collected through linkage to the National Immunisations Management System and questionnaires. Participants had fortnightly asymptomatic SARS-CoV-2 PCR testing and monthly antibody testing, and all tests (including symptomatic testing) outside SIREN were captured. Data cutoff for this analysis was Feb 5, 2021. The follow-up period was Dec 7, 2020, to Feb 5, 2021. The primary outcomes were vaccinated participants (binary ever vacinated variable; indicated by at least one vaccine dose recorded by at least one of the two vaccination data sources) for the vaccine coverage analysis and SARS-CoV-2 infection confirmed by a PCR test for the vaccine effectiveness analysis. We did a mixed-effect logistic regression analysis to identify factors associated with vaccine coverage. We used a piecewise exponential hazard mixed-effects model (shared frailty-type model) using a Poisson distribution to calculate hazard ratios to compare time-to-infection in unvaccinated and vaccinated participants and estimate the impact of the BNT162b2 vaccine on all PCR-positive infections (asymptomatic and symptomatic). This study is registered with ISRCTN, number ISRCTN11041050, and is ongoing. FINDINGS: 23 324 participants from 104 sites (all in England) met the inclusion criteria for this analysis and were enrolled. Included participants had a median age of 46·1 years (IQR 36·0-54·1) and 19 692 (84%) were female; 8203 (35%) were assigned to the positive cohort at the start of the analysis period, and 15 121 (65%) assigned to the negative cohort. Total follow-up time was 2 calendar months and 1 106 905 person-days (396 318 vaccinated and 710 587 unvaccinated). Vaccine coverage was 89% on Feb 5, 2021, 94% of whom had BNT162b2 vaccine. Significantly lower coverage was associated with previous infection, gender, age, ethnicity, job role, and Index of Multiple Deprivation score. During follow-up, there were 977 new infections in the unvaccinated cohort, an incidence density of 14 infections per 10 000 person-days; the vaccinated cohort had 71 new infections 21 days or more after their first dose (incidence density of eight infections per 10 000 person-days) and nine infections 7 days after the second dose (incidence density four infections per 10 000 person-days). In the unvaccinated cohort, 543 (56%) participants had typical COVID-19 symptoms and 140 (14%) were asymptomatic on or 14 days before their PCR positive test date, compared with 29 (36%) with typical COVID-19 symptoms and 15 (19%) asymptomatic in the vaccinated cohort. A single dose of BNT162b2 vaccine showed vaccine effectiveness of 70% (95% CI 55-85) 21 days after first dose and 85% (74-96) 7 days after two doses in the study population. INTERPRETATION: Our findings show that the BNT162b2 vaccine can prevent both symptomatic and asymptomatic infection in working-age adults. This cohort was vaccinated when the dominant variant in circulation was B1.1.7 and shows effectiveness against this variant. FUNDING: Public Health England, UK Department of Health and Social Care, and the National Institute for Health Research.


Subject(s)
COVID-19 Vaccines/supply & distribution , Health Personnel , Occupational Diseases/prevention & control , Occupational Exposure/prevention & control , RNA, Messenger , COVID-19 Vaccines/administration & dosage , Cohort Studies , England , Humans , Prospective Studies , Treatment Outcome
19.
Lancet ; 397(10283): 1459-1469, 2021 04 17.
Article in English | MEDLINE | ID: covidwho-1174548

ABSTRACT

BACKGROUND: Increased understanding of whether individuals who have recovered from COVID-19 are protected from future SARS-CoV-2 infection is an urgent requirement. We aimed to investigate whether antibodies against SARS-CoV-2 were associated with a decreased risk of symptomatic and asymptomatic reinfection. METHODS: A large, multicentre, prospective cohort study was done, with participants recruited from publicly funded hospitals in all regions of England. All health-care workers, support staff, and administrative staff working at hospitals who could remain engaged in follow-up for 12 months were eligible to join The SARS-CoV-2 Immunity and Reinfection Evaluation study. Participants were excluded if they had no PCR tests after enrolment, enrolled after Dec 31, 2020, or had insufficient PCR and antibody data for cohort assignment. Participants attended regular SARS-CoV-2 PCR and antibody testing (every 2-4 weeks) and completed questionnaires every 2 weeks on symptoms and exposures. At enrolment, participants were assigned to either the positive cohort (antibody positive, or previous positive PCR or antibody test) or negative cohort (antibody negative, no previous positive PCR or antibody test). The primary outcome was a reinfection in the positive cohort or a primary infection in the negative cohort, determined by PCR tests. Potential reinfections were clinically reviewed and classified according to case definitions (confirmed, probable, or possible) and symptom-status, depending on the hierarchy of evidence. Primary infections in the negative cohort were defined as a first positive PCR test and seroconversions were excluded when not associated with a positive PCR test. A proportional hazards frailty model using a Poisson distribution was used to estimate incidence rate ratios (IRR) to compare infection rates in the two cohorts. FINDINGS: From June 18, 2020, to Dec 31, 2020, 30 625 participants were enrolled into the study. 51 participants withdrew from the study, 4913 were excluded, and 25 661 participants (with linked data on antibody and PCR testing) were included in the analysis. Data were extracted from all sources on Feb 5, 2021, and include data up to and including Jan 11, 2021. 155 infections were detected in the baseline positive cohort of 8278 participants, collectively contributing 2 047 113 person-days of follow-up. This compares with 1704 new PCR positive infections in the negative cohort of 17 383 participants, contributing 2 971 436 person-days of follow-up. The incidence density was 7·6 reinfections per 100 000 person-days in the positive cohort, compared with 57·3 primary infections per 100 000 person-days in the negative cohort, between June, 2020, and January, 2021. The adjusted IRR was 0·159 for all reinfections (95% CI 0·13-0·19) compared with PCR-confirmed primary infections. The median interval between primary infection and reinfection was more than 200 days. INTERPRETATION: A previous history of SARS-CoV-2 infection was associated with an 84% lower risk of infection, with median protective effect observed 7 months following primary infection. This time period is the minimum probable effect because seroconversions were not included. This study shows that previous infection with SARS-CoV-2 induces effective immunity to future infections in most individuals. FUNDING: Department of Health and Social Care of the UK Government, Public Health England, The National Institute for Health Research, with contributions from the Scottish, Welsh and Northern Irish governments.


Subject(s)
Antibodies, Viral/blood , COVID-19/epidemiology , COVID-19/immunology , Health Personnel , Adult , Asymptomatic Infections , COVID-19/diagnosis , COVID-19 Nucleic Acid Testing , England , Female , Follow-Up Studies , Humans , Male , Middle Aged , Pandemics , Prospective Studies , Reinfection , Risk Factors , SARS-CoV-2
20.
Emerg Infect Dis ; 27(4): 1155-1158, 2021 04.
Article in English | MEDLINE | ID: covidwho-1140631

ABSTRACT

Prospective serosurveillance of severe acute respiratory syndrome coronavirus 2 in 1,069 healthcare workers in London, UK, demonstrated that nucleocapsid antibody titers were stable and sustained for <12 weeks in 312 seropositive participants. This finding was consistent across demographic and clinical variables and contrasts with reports of short-term antibody waning.


Subject(s)
Antibodies, Viral/blood , Antibody Formation/immunology , COVID-19 Serological Testing , COVID-19 , Coronavirus Nucleocapsid Proteins/immunology , Health Personnel/statistics & numerical data , Adult , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/immunology , COVID-19 Serological Testing/methods , COVID-19 Serological Testing/statistics & numerical data , Female , Humans , London/epidemiology , Male , Phosphoproteins/immunology , SARS-CoV-2/isolation & purification , Seroconversion , Seroepidemiologic Studies
SELECTION OF CITATIONS
SEARCH DETAIL